I am running a static analysis with CalculiX (CCX). I first modeled the bonded interface using the *TIE constraint, but the results were unsatisfactory. I then switched to the penalty contact method instead. However, the Pardiso solver produced NaN values during computation.
I tried activating the adjust option to adjust the contact initial state—for the identical mesh model in Ansys, I have to enforce full initial contact to obtain valid results. When I set adjust to values ranging from 0.0001 down to 0.000001, the solver threw an error stating that negative Jacobian matrices exist in some elements. Has anyone encountered similar issues and found effective solutions?
How many nodes/elements do you have in your model ? Did you try with PaStiX ?
This is a very common problem when using adjustment. If the tolerance is too large, the surfaces are too far from each other or the meshes are too misaligned, the elements may become severely distortoed leading to negative jacobian errors. Then it might be best to disable adjustment (tolerance can still be high - tie constraint can work even at a significant distance).
My model contains approximately 110,000 nodes and 270,000 elements. I will provide the legend on Monday. I attempted to employ the Pastix solver, and the error message “err: nan” appeared during the solution phase when the adjust parameter was not added.